How Bats Can Have Deadly Diseases Without Dying

Story by Martha A. Lavallie

In the shadowy realms of the night, where whispers of mystery and intrigue dance with the stars, there exists a creature both misunderstood and marveled at: the bat.

Often cast as the villains in tales of horror and disease, these nocturnal beings harbor secrets far more fascinating and beneficial than many might believe.

Science sheds light on bats’ unique abilities and offers hope for medical advancements.

The Misunderstood Marvels of Nature

Bats, the only mammals capable of sustained flight, have captivated human imagination for centuries. Yet, their association with deadly diseases like Ebola, COVID-19, and the Nipah virus has painted them as harbingers of doom.

But what if I told you that there’s more to these creatures than meets the eye?

The Flight of the Bats

Bats in flight elevate their basal metabolic rate 15-fold ¹, heart racing at over a thousand beats per minute, and body temperature soaring to near-lethal limits.

Such extreme physiological feats are not just for show; they’ve shaped the very essence of bat biology, making them resilient beings in the face of what would be insurmountable stress for other mammals.

Bats exhibit a remarkable ability to modulate their body temperature and metabolic rate, entering torpor-like states at temperatures as high as 32°C, a strategy that allows them to conserve energy in unpredictable environments.

Their heart rates, a direct measure of energy expenditure, can plummet to as low as 40-50 beats per minute when resting, indicating a profound ability to reduce metabolic demands.

This flexibility is crucial for survival, especially in tropical climates where food resources can be ephemeral and unpredictable.

Viral Tolerance Is Bats’ Superpower

Unlike humans, who can suffer severe symptoms and even death from viral infections, bats have evolved ² unique molecular pathways that make them exceptionally tolerant to viruses. Their immune systems are a marvel, with certain species having an alarm switch perpetually on, ready to combat viruses before they can take hold.

Bats dampen inflammation through reduced expression of TNFα and other inflammatory cytokines while upregulating anti-inflammatory ones like IL-10. They also exhibit a robust interferon response to RNA viruses and have adaptations that counteract inflammation, such as significantly dampened activation of the NLRP3 inflammasome.

These adaptations allow bats to coexist with viruses, controlling inflammation more effectively than ramping up the immune system, which could lead to a cytokine storm and exacerbate disease. This doesn’t just make them fascinating subjects of study; it positions them as potential keys to unlocking new ways to treat diseases in humans.

Learning from the Winged Wonders

The resilience ³ of bats isn’t just an academic curiosity; it’s a beacon of hope in the field of medicine. Researchers are studying bats to mimic their viral defense mechanisms, hoping to revolutionize how we treat diseases like COVID-19.

The use of drugs like Remdesivir and dexamethasone in treating severe COVID cases is just the beginning. By understanding and emulating the bats’ immune responses, particularly their ability to limit inflammatory responses upon infectious challenges, we could usher in a new era of medical treatments.

Insights into bat immunity can contribute to comparative mammalian immunology, aging, longevity, and immunometabolism, offering a promising avenue for future therapeutic strategies.

Protecting Bats, Protecting Ourselves

But there’s a catch. Bats, like all creatures, are vulnerable to the stresses of environmental changes and human interference. Studies ⁴ indicate that bats under extreme stress are more likely to shed and spread viruses.

Factors like habitat destruction, climate change, and physiological stressors can disrupt bats’ immune balance, leading to increased viral replication and shedding. This makes the conservation of bats not just an ecological concern but a public health imperative.

A healthy bat population is less of a zoonotic threat and more of a valuable ally in our quest to understand and combat diseases. Ensuring their well-being could be crucial in preventing future spillovers and outbreaks.

Embracing the Night’s Guardians

It’s clear that bats are not villains but rather unsung heroes. Their unique biology not only fascinates but also holds the key to medical advancements that could change the world.

So, the next time you think of bats, remember their role as the potential saviors in our ongoing battle against diseases.

References

  1. ncbi.nlm.nih.gov/pmc/articles/PMC5750026/
  2. ncbi.nlm.nih.gov/pmc/articles/PMC7341951/
  3. nature.com/articles/s41577-021-00523-0
  4. ncbi.nlm.nih.gov/pmc/articles/PMC6410205/
  

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